WordNet records no synonym and no antonym for pluralist. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a cleric who holds more than one benefice at a time
a philosopher who believes that no single explanation can account for all the phenomena of nature
someone who believes that distinct ethnic or cultural or religious groups can exist together in society
Synonyms, antonyms and the broader and narrower relations for pluralist come from Princeton University’s WordNet. Full sources and licences.